One famous Leonardo da Vinci rapid-fire cannon design had 33 barrels.
The weapon arranged its barrels in three rows of eleven. The design was intended to let one row fire while another cooled and a third was reloaded. Mounted on a wheeled frame, it aimed to combine mobility with a higher rate of fire than a single cannon could provide.
Leonardo’s multi-barrel weapon is sometimes described as a precursor to the modern machine gun, but that comparison has limits. The barrels were separate guns rather than a continuous automatic firearm, and the design depended on manual loading, aiming, and ignition. No reliable evidence shows that Leonardo’s exact device entered military service.
The concept reflects a recurring feature of Leonardo’s military engineering: he tried to solve practical battlefield problems through mechanical organization. Cooling, reloading, and transport were all addressed in the same proposal.